#include<iostream>
#include<algorithm>
#include<map>
using namespace std;
const int N = 2e5 + 10;
map<int, int>mp;
int arr[N];
int n;
int main()
{
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> arr[i];
	}
	int ans = 0;
	sort(arr, arr + n);
	for (int i = 0; i < n; i++) {
		if (mp[arr[i] - 9]) continue;
		mp[arr[i]] = 1;
		ans++;
	}
	cout << ans << endl;
	return 0;
}